1. Field of the Invention
This invention relates to temperature control in an distributed air conditioning system.
2. Background Art
The basic configuration of this type of a distributed air conditioning system is such as shown in FIG. 3 that the system comprises a system for cooling or heating air in a room 85 to be air conditioned by providing a heat source 10 for cooling or heating to an indoor unit 20 from a heat source unit 10, a system for setting cooling or heating operation conditions from an operation unit 30 installed in the room 85 to be air conditioned through the indoor unit 20 and monitoring and controlling a required operation out of all the operations by means of a central monitoring and control board 50, and a system for directly monitoring detection values of monitoring meters 86 installed in the room 85 to be air conditioned, for measuring temperature and humidity in the room by means of the central monitoring and control board 50. The term "air conditioning" includes three cases: one where only cooling is carried out, one where only heating is carried out and one where cooling and heating are selectively carried out.
This air conditioning system uses a heat source obtained by a compression refrigerating cycle or an absorption refrigerating cycle. For instance, a system using a heat source obtained by a compression refrigerating cycle is configured to obtain a heat source from a heat operation fluid compressed by a heat source unit 10 as shown in FIG. 3, as disclosed by Laid-open Japanese Patent Application No. Hei 6-146987, for example.
In FIG. 3, circuit portions shown by a double line are pipe lines of a heat operation fluid for obtaining a heat source, e.g., a refrigerant. Circuit portions shown by a thin line are cable lines for electric detection signals and control signals. Since the heat source unit 10 is generally disposed outdoors, it is also called "outdoor unit", but it may be disposed indoors.
The compression section 11 of the heat source unit 10 is a section where a rotary compressor is driven by a drive source such as an engine or a motor to pressurize a heat operation fluid for obtaining a heat source, such as a refrigerant exemplified by freon R22, freon R137 or the like and the pressurized heat operation fluid is provided to a pipe line passing through the heat exchanger 12 of the heat source unit 10 and the heat exchanger 21 of the indoor unit 20 so that the heat operation fluid whose pressure is reduced by the completion of a required heat operation returns to the compression section 11 to be pressurized again.
The passage switching section 13 of the heat source unit 10 is a section for connecting pipe lines in such a manner that the heat exchanger 21 of the indoor unit 20 functions as an absorption heat exchanger and the heat exchanger 12 of the heat source unit 10 functions as a discharge heat exchanger in order to cause the indoor unit 20 to carry out cooling operation, or the heat exchanger 12 of the heat source unit 10 functions as an absorption heat exchanger and the heat exchanger 21 of the indoor unit 20 functions as a discharge heat exchanger in order to cause the indoor unit 20 to carry out heating operation and is a passage switching section for electrically operating a switching valve such as a four-way valve.
The control section 70 of the operation unit 30 stores data on a room temperature value D1A detected by a temperature detector D1, data on operation conditions such as a target temperature value TA for cooling or heating which are set and input by a setting operation section 76, and data on operation start/stop. The control section 70 supplies required data out of these data to the control section 70 of the indoor unit 20 through a communication line 82. Since the operation unit 30 has a function to remotely control the indoor unit, it is generally called "remote controller".
The control section 70 of the indoor unit 20 stores a room temperature value D2A detected by a temperature detector D2, other detection data, data given by the operation unit 30 and the like, controls a flow control valve V2 for supplying a heat operation fluid to the heat exchanger 21 and the quantity of air of a fan (not shown) for supplying air in the room to the heat exchanger 21 so that the room temperature value D2A can reach a target temperature value TA given by the control section 70 of the operation unit 30, and provides required data on operation start/stop and operation conditions to the control section 70 of the heat source unit 10 and the control section 70 of the central monitoring and control board 50 through the communication line 81.
The control section 70 of the heat source unit 10 stores a room temperature value D4A detected by a temperature detector D4, other detection data, data given by the indoor unit 10 and the central monitoring and control board 50, and data on an instruction signal, controls the switching of the flow direction of the passage switching section 13, a flow control valve V1 for supplying a heat operation fluid to the heat exchanger 12, and the quantity of air of a fan (not shown) for supplying air in the room to the heat exchanger 12 based on these data, and provides required data on operation start/stop and operation conditions to the control section 70 of the central monitoring and control board 50 through the communication line 81.
The control section 70 of the central monitoring and control board 50 stores a room temperature value D5A detected by a temperature detector D5, other detection data, data on operation start/stop, operation conditions and the like which are set and input by the setting operation section 76, data given by the indoor unit 10 and the heat source unit 20, and a room temperature value D3A detected by a temperature detector D3 of a monitoring meter 86, displays required data out of these on a display section 77, and provides required data on operation start/stop, operation conditions and the like to the control section 70 of the indoor unit 20 and the control section 70 of the central monitoring and control board 50 through the communication line 81.
Each of the control sections 70 provided in the heat source unit 10, the indoor unit, the operation unit 30 and the central monitoring and control board 50 is mainly composed of a control processing function (to be referred to as "CPU" hereinafter) of a microcomputer and is constructed by using a commercial CPU board (CPU/B) in the control section 70 as shown in FIG. 4, for example. Data obtained from each detection signal obtained by detecting the state of each section and each operation signal input by operating the setting operation section 76 and data provided from other control sections 70 through a communication connection terminal 78 to be described later are taken from an input/output port 71 as input data and stored in a working memory 73 such as a RAM. Each control signal for controlling each section obtained by carrying out required control processing based on these data, a processing flow program prestored in a processing memory 72 such as a ROM and data on reference values stored in a data memory 74, such as an electrically rewritable PROM, that is, EEPROM, as well as data signal to be provided to other control sections 70 are output from the input/output port 71.
A time required for control processing is counted by a timer circuit 75, data on setting conditions such as the operation conditions and control conditions of sections are displayed on the display section 77, and further the communication connection terminal 78 is provided to transmit and receive control data over communication lines 81 and 82 between the control sections 70, such as an extension line of a bus line or a communication cable. This communication connection terminal 78 is formed of a communication connection terminal using a communication IC based on RS485 standards, for example, as required. The communication line 82 between the control section 70 of the operation unit 30 and the control section 70 of the indoor unit 20 may be formed of a radio transmission line for optical communication such as infrared light. In this case, a radio transmission and receiving function for the radio transmission line is provided in the communication connection terminal 78.
In the configuration of FIG. 3, one indoor unit 20 is connected to one heat source unit 10 (to be referred to as "one heat source unit/one indoor unit configuration" hereinafter). Besides, a configuration in which a plurality of indoor units 20 are connected to one heat source unit 10 (to be referred to as "one heat source unit/a plurality of indoor unit configuration" hereinafter) and a configuration in which a plurality of indoor units 20 are connected to a plurality of heat source units 10 (to be referred to as "a plurality of heat source units/a plurality of indoor unit configuration" hereinafter) are already known. Further, in the configuration of FIG. 3, one operation unit 30 is provided for each indoor unit 20 (to be referred to as "one indoor unit/one operation unit configuration" hereinafter). However, a configuration in which one operation unit 30 is shared by a plurality of indoor units 20 (to be referred to as "a plurality of indoor units/one operation unit configuration" hereinafter) is also known.
As for the configuration of the above distributed air conditioning system 100, the heat source unit 10, the indoor unit 20, the operation unit 20 and the central monitoring and control board 50 are installed in separate buildings, or these units are installed in a single building.
Where these units are installed in a single building and the above "one heat source unit/one indoor unit configuration" and "a plurality of heat source units/a plurality of indoor unit configuration" are combined with the central monitoring and control board 50, as shown in FIG. 5, for example, the heat source units 10 are installed on the roof, the indoor unit 20 and the operation unit 30 are installed in each room 85 to be air-conditioned on each floor, and the central monitoring and control board 50 is installed on the lowermost floor, such as a basement. In FIG. 5, each pipe line through which a heat operation fluid flows is depicted by a bold solid line to represent forward and backward pipe lines.
To obtain a heat source by an absorption refrigerating cycle, a group of the compression section 11, the heat exchanger 12 and the passage switching section 13 is changed to a group of an absorber for carrying out heat operation by circulating an absorption solution such as a mixture of water and ammonium, a regenerator, a condenser and an evaporator, and a second heat operation fluid such as water is caused to circulate in a pipe line passing through the evaporator to obtain cold water or hot water and is provided to the heat exchanger 21 of the indoor unit 20.
Like a general air conditioning system, the above distributed air conditioning system 100 of the prior art carries out air conditioning such that a room temperature value D2A detected by the temperature detector D2 provided in the indoor unit 20 which is considered as a substantial room temperature value can reach the target temperature value TA.
However, the temperature detector D2 provided in the indoor unit 20 is liable to malfunction due to the deterioration of detection elements caused by repetitions of vibration of a fan for supplying air in the room to the heat exchanger 21 or dew condensation. When the temperature detector D2 malfunctions, there is such inconvenience that the indoor unit 20 operates erroneously.
To prevent this, the system is generally constituted to stop its operation. Therefore, until the repair of a damaged portion is completed, the room 85 to be air conditioned such as a gust room of a hotel cannot be cooled or heated with the result of such inconvenience that unexpected damage is sustained.
Therefore, it has been desired to provide a distributed air conditioning system free from such inconvenience.